1. Field of the Invention
This invention relates to the production of integrated circuit (IC) devices and in particular to a method of bonding lead wires to the IC for providing electrical signal paths.
2. Description of the Prior Art
In the typical process of producing IC devices, an IC die which has IC logic circuits formed on its surface, is attached to a die attach pad of a lead frame. The lead frame has a number of electrically conductive elements or fingers that are connected to the IC circuits by lead wires which are bonded to contact points or bonding pads of the IC circuits A large number of wires need to be bonded to the IC die surface and to the attach pad, which are relatively small in dimension. With the present approach to mass production of IC devices at high speeds and low cost, automated bonding apparatus which is under control of a microcomputer is employed. T implement the wire bonding process successfully, it is necessary that the wire bonding points be fixed precisely in position so that there will not be any electrical circuit shorting or erroneous connections to the IC elements.
When the IC die is attached to a flexible tape-like structure, such as disclosed in the aforementioned patent application, the flexible structure has a tendency to float and vibrate so that during the wire bonding process accurate fixed positioning of the conductive elements formed with the structure is difficult. Prior art approaches to wire bonding to a lead frame utilize a window clamp to fix the frame and associated conductive elements in a rigid position. However, a window clamp which attaches to the periphery of a flexible structure does not effectively prevent the inner portions of the structure, from vibrating or being displaced from a reference plane. Therefore, bonding of wire leads to an IC assembly, where space is limited and speed of production is highly desirable, poses problems that require effective solutions.